No matter how hard you try, you cannot hide from springtime allergens. They are ubiquitous.

About 15 percent of those inflicted with allergies this time of year are reacting to tree pollen, which can travel up to 400 miles and is easily inhaled. The other 85 percent of us are affected by grass pollen, which is equally annoying. In either case, the symptoms are the same: itchy and watery eyes, stuffy and runny nose, scratchy throat and maybe wheezing if you also have asthma.

While we now recognize this malady as springtime or seasonal allergies, back in the late 18th and early 19th century the condition was less well understood. Back then, a link was made between hay season and cold-like symptoms. Thus, when someone developed cold-like symptoms from the end of May to end of July, they were often diagnosed with “hay fever.”

By the mid-19th century, however, studies were being done on the reproduction of plants, and it was determined that they reproduce sexually. That’s how pollen was discovered. Some plants were discovered to be pollinated by bees and others by wind.

Around that time, one of the greatest scientists of all time, Louis Pasteur, learned that some diseases were caused by tiny microbes. Other doctors soon picked up on Pasteur's ideas, including Dr. Charles Blakely.

Blakely suffered from severe hay fever, and he believed his condition was the result of exposure to grass pollen, not hay. So he decided to perform tests on himself to prove his theory.

Terry Allen Hicks, in his book "Allergies," (2006, China, page 40) describes how Blakely saved some grass pollen in a jar until winter. When all the grass was dead, he opened the jar, inhaled, and almost immediately started sneezing. It was clear that his allergy symptoms were not caused by hay, but pollen.

Yet the diagnosis of 'hay fever' was so ingrained in our medical nomenclature that it stuck. The irony is that a 'fever' has never been part of the diagnosis. People with allergies don't get fevers.

More appropriate terms for hay fever are either seasonal allergies or, scientifically speaking, nasal rhinitis.

We now know that grass pollen is harmless for most people. It bothers only the 10 percent of us who have developed allergies. That means our immune systems have an abnormal response, or hypersensitivity, to various allergens, such as grass pollen.

The first time you were exposed to grass pollen, your body treated it like an enemy combatant, and it developed antibodies. Every subsequent time you are exposed to grass pollen, your body recognizes that pollen and goes to war with it.

In the reaction that ensues, histamine and leukotrienes are released into your bloodstream and that causes inflammation of the tissue around your eyes and respiratory tract. It's this inflammation that leads to allergy symptoms. This can also be an asthma trigger in people with asthma. This is why your asthma acts up during grass pollen season.

Jon C. Hopwood, in "What Are Grass Pollen Allergies?" describes grass pollen as microscopic round and oval-shaped grains that contain the plant's seed. The wind picks the pollen up and carries it for miles and miles so grass can grow anywhere.